Image projecting comparison microscope



July 1, 1947. BUTSCHER 2,423,370

IMAGE PROJECTING COMPARISON MICROSCOPE Filed June 30. 1942 2 Sheets-Sheet 1 Iizv 610 i501 I 6 B wts 01 er July 1, 1947.

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1 Eloise/Eel Patented July 1, 1947 UNITED STATES IMAGE'PRQJI I-CTING COMPARISON 'MI Q QPE Bu ch r i nn S itze la d: a ign; b rnesne assignments, to A ..Gr Mechaniscl e Optische Erfi-ndungen, Chur, Switzerland, a

I :ie mtwlwompan of Switzerland Application June 30, 1942=,Serial"No.' 449,125

In: Switzerland 15,1 194 moyable or stationary lined glass plates inserted between objective; and eyepiece and comparison microscopes which; by means of an intermediate optical system project a scale, a profile plate or an original piece, agreeingin scale with the piece tobe tested, on to the object plane of the microscope system. Lined plates can only be made and -E JFQQ 2 p i ifl-l fitfil however, puts the user to-considerableexpense and loss of time. The same is to be said for a comparative measure for'W Qh: ither a in pla eaa e in Scale w ih e erieieal iec o n r a ec is ecessa he e ta. iffi ult s: a s r he e as it is practically impossible for him to make such small drawings as the lined plates used hitherto, especially if higha'accuracy is required.

The present invention remedies these inconveniences. The microscope according to the invention is characterised in that it is combined with an optical projection device allowing the image of an enlarged comparison means to be viewed simultaneously with the image of the object to be tested.

The enlarged comparison means may be an enlarged drawing (a so-called reference drawing), an enlarged scale, an enlarged rule, an enlarged model, etc. Lined glass plates or profile plates are thus no longer needed. In most cases an enlarged drawing is used. This drawing can be made at any time and without difiiculty in any technical office on a suitable transparent material. The magnification of the microscope is chosen according to the size of the object to be tested, e. g. 10, 20, 30 fold, etc. The reference drawing is then preferably made on the scale of the magnification used, for instance, on the scale :1, 20: 3 :1, etc. This allows of a very exact preparation of the reference drawing.

As the comparison means can be inserted by the user into and removed from the apparatus at will, the same apparatus may be used for the most various profiles and magnifications. EX- pense and loss of time for the manufacture and mounting of lined and profile plates are thus avoided.

The accompanying drawings illustrate, by way of examples, in

Fig. 1 a scheme of an embodiment 2 alongitudinal section of another embodiment of, the microscope and Fig. 3 a view from the right in Fig. 2.

r The microscope itself has an object carrier I formed as a movable plane table or measuring table vertically adjustable by means, of a hand wheel 23 and a spindle 24 and provided with wellii-blown. measuring spindles. 25. and 2,6; crossing each other, the. object 2 to: be tested resting on this table. The diascopic illumination. is ob.- tained; by a light source 3 whose rays go through th condenser '4 (Fig. 1) and through an adjust,- ab e diaphragm 5 and fall-upon the mirror 6 deviating them towards the collimator objective 7 which they leave in a parallel-statein order, afterwards, to, illuminate the-object ltobetested. Ln-the embodiment according tov Figs. 2 and 3 th condenser 4 is lacking.) From here, the rays reachthe microscope-objective 8,. are..deviated in-the prism or mirror system I 9, and go through the eyepiece I,-I into the eye I2.

The projection device combined with the microscope has a glass; plate I3 upon which the. enateed eq pae oe m a s. e. a a nla e erence drawing, II;- on a, suitable transparent ma- .terraLis laid. The glass plate I3a isfixed to the mounting 21 connected with the detachable cap 29 by means of the pins 28. This cap and with it the glass plate is movable and serves to press the inserted drawing flat. The drawing I6 which may be exchanged very quickly, is illuminated by the light sources I4 (Fig. 1) or the tubular light source 39 (Fig. 2). In order to obtain a uniformly illuminated surface, a translucent diffusing means, 8. g., an opaque glass disc I5, is inserted between the light sources I4 and the plate I3a. As is shown in Fig. 2, the glass plate I3a presses the drawing I6 flat against the glass plate I3. The light rays are deviated by the mirror ll and, after having passed through a diaphragm I8, enter the objective I9. This objective I9 is preferably mounted stationarily and, on changing the magnification, need neither be replaced nor must its projection distance be changed. The combination of the image rays of the microscope and the projection system takes place in the partially permeable mirror or prism system Ill, and in the eyepiece both the'object image and the image of the drawing are simultaneously visible.

A movable lined plate 22 may be inserted into the eyepiece, adapted to be used for special measurement such as, e. g., for measuring angles. The latter may be read on a circular division 3| in a similar way as is the case in the well-known profile testing microscopes. The object images themselves, however, are tested with the image are particularly well-suited, which, when combined appear white. Into the ray path of the microscope, for instance, a red filter 20 and into the ray path of the projection device a green filter 2| is inserted. In this way the image of the drawing 16 appears red and that of the object 2 green on a clear ground, so that after the superimposition of the two images even the smallest differences are distinctly contrasted while the superposed parts appear black in the clear eyepiece field. Besides, the, object image and the image of the comparison means always unequivocally differ from each other by their difierent colours.

The focusing is carried out by moving the p ane table I.

It is clear that the details of the apparatus may undergo various modifications with regard to the scheme illustrated without departing from th spirit, of the invention. It might also b provided with several magnifying powers. Then, the objectives and the condensers would preferably be arranged on movable carriers. The plane table may be replaced by an ordinary object carrier.

What I claim is:

1. In an optical apparatus, a holder for an errlarged comparison means, means for projecting an illuminated image of said comparison means, a measuring microscope, and means for combining the image of the comparison means formed by said projecting means with the image of the object to be tested formed by said microscope to enable simultaneous viewing thereof.

2. In an optical apparatus, a holder for an enlarged drawing of the object to be tested, means for projecting an illuminated image of said draw- 4 ing, a measuring microscope and means for combining the image of said drawing with the image of the object to be tested formed by said microscope to enable simultaneous viewing thereof.

3. An apparatus as claimed in claim'l, characterized by the provision of color filters for coloring the several images.

4. In an optical apparatus, a measuring microscope, a holder for an enlarged comparison means, means for projecting an illuminated image of said comparison means, said projecting means including an objective with a projection distance constant over all magnifying powers of said measuring microscope, and means for combining th image of the comparison means formed by said projecting means with the image of the object to be tested formed by said microscope to enable simultaneous viewing thereof.

5. In an optical apparatus, a measuring microscope,'a holder for the image to be tested arranged djacent said microscope, a holder for an enlarged comparison means, means for projecting an illuminated image of said comparison means, one of said holders being stationary and the other adjustable, and means for combining the image of the comparison means formed by said projecting means with the image'of the object to be tested formed by said microscope to enable simultaneous viewing thereof.

KARL BUTSCHER.

REFERENCES CITED The following references are of record in the file of this patent: h 

